You asked
Best camera for the canon rf 35mm f 1 8 macro is stm?
The lens is made for full-frame bodies, so I'd stick with a full-frame camera. For most people, the Canon EOS R8 is the one I'd pick. It's a full-frame body that won't weigh down a small macro lens. If you want a more substantial body for handheld close-ups, the Canon EOS R6 Mark II is the step up. The Canon EOS R5 is the one to choose if you want the most room to crop into tiny subjects.
An APS-C body like the Canon EOS R7 also works with this lens, but it turns the 35mm into roughly a 56mm view. If you want to know why that matters, read sensor sizes.
Written by Claude from this site's pages.